This proposal discusses a project aimed at delineating the tissue-specific effects of the ecdysone steroid hormone. Generally, we aim to define the molecular mechanisms that regulate the dynamic responses observed in steroid hormone signaling. Steroids are naturally occurring molecules necessary for the development and homeostasis in animals and their derivatives are targets of many therapeutic treatments. We will use functional genomics to define a catalog of steroid hormone target genes on an entire genome scale. I will use whole genome tiling arrays to map genome wide DNA-protein interactions for the Ecdysone receptor using unique cell/tissue types. We will utilize computational techniques to examine both expression changes and EcR binding sites of target genes, ultimately revealing the tissue specific and/or EcR isoform specific gene targets. The tools refined during the completion of this endeavor will outline the backbone for a systematic large scale application to define similar catalogs of tissue-specific transcriptional regulators. These applications may be important for future studies where genomic analyses of gene expression are used to determine prognosis of hormone treatments and diagnosis of hormonal related disorders.